Income Taxes Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2010
Income Taxes [Line Items]
Increase Decrease In Income taxes Payable Current	$ 12.5
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits	157.6
Income (Loss) from Continuing Operations before Income Taxes, Foreign	394.7	383.7	321.1
Deferred Tax Liability Not Recognized, Cumulative Amount of Temporary Difference	1,489.9
Deferred Tax Liability Not Recognized, Amount of Unrecognized Deferred Tax Liability	442.9
Net deferred tax assets	165.0	165.9
Foreign Income Tax Expense (Benefit), Continuing Operations	4.4	10.4	0
Income Tax Holiday, Income Tax Benefits Per Share	$ 0.02	$ 0.05
Current Foreign Tax Expense (Benefit)	54.3	55.9	48.4
Gross unrecognized tax benefits	212.7	201.1	188.4	178.2
Amount of gross unrecognized tax benefits that would impact the effective tax rate, if recognized	202.1
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	1.9	2.4	1.9
Valuation Allowance of Deferred Tax Assets California
Income Taxes [Line Items]
Valuation Allowance, Deferred Tax Asset, Change in Amount	3.8	4.6	3.9
Domestic Country
Income Taxes [Line Items]
Operating Loss Carryforwards	36.6
State and Local Jurisdiction
Income Taxes [Line Items]
Operating Loss Carryforwards	249.8
State and Local Jurisdiction and the Internal Revenue Service [Member]
Income Taxes [Line Items]
Operating Loss Carryforwards	14.7
Research
Income Taxes [Line Items]
Tax Credit Carryforward, Amount	86.1
California State Research
Income Taxes [Line Items]
Tax Credit Carryforward, Amount	43.5
Canadian
Income Taxes [Line Items]
Tax Credit Carryforward, Amount	49.7
Foreign Country
Income Taxes [Line Items]
Tax Credit Carryforward, Amount	$ 60.8
Minimum
Income Taxes [Line Items]
Operating Loss Carryforwards, Expiration Dates	2014-12-31
Minimum | Federal Research
Income Taxes [Line Items]
Tax Credit Carryforward, Expiration Dates	Dec. 31, 2021
Minimum | Canadian
Income Taxes [Line Items]
Tax Credit Carryforward, Expiration Dates	Dec. 31, 2025
Minimum | Foreign Country
Income Taxes [Line Items]
Tax Credit Carryforward, Expiration Dates	Dec. 31, 2022
Minimum | Europe and Asia Pacific [Member]
Income Taxes [Line Items]
Tax Credit Carryforward, Expiration Dates	Dec. 31, 2016
Maximum
Income Taxes [Line Items]
Operating Loss Carryforwards, Expiration Dates	2032
Maximum | Federal Research
Income Taxes [Line Items]
Tax Credit Carryforward, Expiration Dates	Dec. 31, 2033
Maximum | Canadian
Income Taxes [Line Items]
Tax Credit Carryforward, Expiration Dates	Dec. 31, 2033
Maximum | Foreign Country
Income Taxes [Line Items]
Tax Credit Carryforward, Expiration Dates	Dec. 31, 2023
Maximum | Europe and Asia Pacific [Member]
Income Taxes [Line Items]
Tax Credit Carryforward, Expiration Dates	Dec. 31, 2019